It wasn't long after Gregg Carey was voted off ''Survivor: Palau" that US newspapers were full of real-life survivors, folks who'd been left homeless by the tsunami in South Asia. ''It put my experience, my fame, in perspective," said Carey, who grew up in Ashland and lived in Boston before moving to Chicago. ''I have a soft spot for what happened over there." (Carey, you'll recall, lasted until the 12th of 14 episodes of ''Survivor: Palau," which was eventually won by fireman Tom Westman.) To the extent he has any, Carey's using his celebrity now to help those other survivors. With the aid of his CBS castmates, Carey has created the Tsunami Challenge, an effort to aid the tiny fishing village of Villachchenai. (Check out www.thetsunamichallenge.org.) ''I never asked to be on '' 'Survivor,' I was picked out at a bar," Carey said. ''But things happen for a reason."